Use of furfural in grease manufacture



Patented July 25, 1950 USE OF FURFURAL IN GREASE MANUFACTURE Arnold J. Morway, Clark, N. ,1, assignor to standard Oil Development Company, a corporation of Delaware No Drawing. Application November 17, 1948, Serial No. 60,616

The present invention relates to the use of furiural in grease manufacture, and relates more particularly to the economical use of the furfural content of solvent treated lubricating oilsemployed in the manufacture of lubricating greases.

As is well known in the art, certain solvents, of which furfural is an important example, are used in refining lubricating oil stocks, In order to remove aromatic and unsaturated constiutents so as to leave an unextracted portion (rafiinate of good quality and essentially consisting of paraffinic hydrocarbons, certain Mid-continent and Coastal stocks and other lubricating oils of various grades are treated with furfural to extract therefrom the aromatic constituents and a substantial proportion of olefinic hydrocarbons. The extracted portion is commonly treated to recover the furfural by distillation. The raffinate, which is the lubricating oil of high quality, contains a minor proportion of the solvent furfuralwhich must be removed, and this usually is accomplished by distillation. In addition, either the rafiinate or the extract, or both, may be washed with water to further remove furfural and other undesired ingredients in the oils, and this water may be treated to recover f-urfural.

It will thus be seen that in conventional prior art processes employing furfural for solvent ex traction purposes, there are three components Which may be treated to recover furfural. present invention is based upon the discovery that any one of these constituents, or any two; or all three, may be used directly in the manufacture of grease making, it being unnecessary to conduct the usual recovery operations to recover furfural or to remove it from the oil.

In a oopendin-g application, Serial No. 60,615 filed by the present inventor and J. J. Kolfen- The 1 Claims. (01. 252 41) I into grease may thus be obtained inexpensively and eliminate a usual processing step. The water which contains furfural also may be used in grease forming processes. For example, a strong sodium hydroxide solution is added to the waterfurfural solution in such an amount that the final concentration is, say, 33 sodiumhydroxide. The furfural undergoes the Cannizzaro reaction, forming sodium furoate'and furfuryl alcohol. In the grease cooking operation, the water is of course evaporated. The furfuryl alcohol pro duced in the Cannizzaro reaction is preferably removed fi'om the grease, either completely or to a considerable extent, ,during the cooking of the grease. The alkali which is used to convert furfural into the acid and alcohol is preferably the same which isemployed to saponiiy the fatty material to produce the grease thickening soap but may be a different alkali if a preformed soap is used.

In the conventional process for treating lubricating oils with furfural, a vertical counterflow extraction'tower is provided with the necessary shell and tube heat exchanger equipment for continuous treatment with the solvent at a desired controlled flow rate and temperature. The refined oil, which is the raffinate, is drawn off at the top. of the column and the extract is removed at. the bottom. I The raffinate contains a small amount of the solvent furfural, although the major portion is in the extract.

Where the rafiinate oil is used to form the grease, as is usually the case, its furfural content is determined, and if excessive, this oil is diluted with other oil which is free from furfural to re duce the concentration to a desired level. On the other hand, if the furfural content of the oil is too low additional furfural may be added, or

bach on November 1'7, 1948, there is described a process by which certain aldehydessuch as furfural may be treated with an alkali such as sodium hydroxide to convert the aldehyde to the corresponding furoic acid and iurfuryl alcohol according to the well-known Cannizzaro reaction.

As described in said application, furfural, which is abundantly available as a by-product of certain cereal manufacturers, may be used as a source of furoic acid, the furoic acid having the desired property of modifying and improving the the'water extract which is obtained by recovering the water used to wash the extract or the rafiinate may be employed. Preferably, the furfural content of the oil is in the neighborhood of 10% by weight although quantities as small as about 2% or as large'as 20% may be used in some cases.

Example are formed. Thereafter, by weight of fatty acid, preferably hydrogenated. fish oil acids of 12 to 22 carbon atoms, or other substantially saturated acid such as stearic acid, is added together with 2.25% by Weight of sodium hydroxide, sufficient to neutralize the fatty acid.

The ingredients described are combined in a grease kettle and the complete mass is heated to a temperature of 400-450 F. while mixing is continued. Thereafter, the mass may be worked in the kettle while cooling or may be run into pans.

and allowed to cool with subsequent reworking in the kettle and milling in a grease mill or other suitable homogenizing equipment. Where the grease is cooled in the kettle with continuous working, it may be filtered and packaged after the temperature drops below 200 F.

Instead of using the rafi'lnate or high paraffinic oil, the extract which contains asphaltic, aromatic and unsaturated aliphatic hydrocarbon ingredients may be used to produce an improved low cost grease such as cheap steel mill or railroad greases. In such case, the furfural content should be controlled as in the foregoing example.

Furfural may be incorporated into standard greases to improve their high temperature properties by using therecovered Water of high furfural content from the solvent refining process, adding sufficient alkali, preferably sodium hydroxide, to carry out the Cannizzaro reaction, thusincorporating the salt of furoic acid in the grease. The quantity of water used will be dependent upon its furfural content as well as upon the desired furoic acid salt content of the finished grease. As pointed out in the copending application referred to above, the furoic salt content, e. g. sodium furoate, of the finished grease composition should be between 2 and of the total weight, proportions of about 3 to 12% being preferred.

Other oils than petroleum oils may be refined with furfural such as certain of the vegetable and marine oils. The purpose of such treatment usually isthe removal of the highly unsaturated oils such as the drying oils. The latter are not particularly useful in grease making because of their lack of oxidation resistance. Hence, the extract fraction from such processes is not useful for the purposes of this invention, but the 60 combinations.

4 separating the furfural. In this embodiment of the invention, the rafiinate non-drying oil, with appropriate furfural content, may be used to replace the fatty oil or fatty acid and the furfural required for the Cannizzaro reaction as well as for the required saponification.

It will be seen from the foregoing that the present invention contemplates the utilization of a, furfural-containing efiiuent from a solvent refining process, either of mineral oil or fatty oil (or acid) refining, wherein the efliuent is subjected to the Cannizzaro reaction to obtain a metal furoate, accompanied or followed by a saponification step whereby both a furoate salt and a soap are formed. The lubricating oil, which may be either in the efiluent or may be added to the reaction, is supplied in proper proportions to form a grease and the proportions of furfural (about 2 to 20%) of fatty material (about 3.to 30%) and saponifying agent (about 1 to 8%) are adjusted as desired. The proportionsindicated are by weight, the alkali or other saponifyingv agent being calculated on a dry weight basis.

Where the effluent from the solvent treating process contains a major proportion of lubricating oil (usually mineral base lubricating oil), the furfural content is adjusted as previously described and the required quantities of alkaline material (saponifying agent) and fatty material are incorporated therein. Where the effluent is from a fatty oil or fatty acid treating process, the lubricating oil and alkaline material are added in the required proportions. Where the effluent containing the furfural is largely aqueous, both the fatty material and the lubricating oil must be added.

The sequence of steps isrelatively unimportant although it is preferable, where possible, to carry out the Cannizzaro reaction prior to or simultaneously with the saponification and not after saponification.

The example above involved the use of substantially saturated hydrogenated fish oil acids of 12 to 22 carbon atoms, such as Hydrofol 54, in proportions of 15% of the weight of the total ingredients. Various other fatty acids and their glycerides were tested in various proportions and These are tabulated as follows:

Table Percent D g r i t 'l Per- Pen mm [10 e515 Wheel Be in a Furfural Hlgh Molecular Weight Sapomfiable Type ping ance, at g Time Hrs. 5 Chgd. cent Pt., F. x looooox Percent Test 220 p. s. i. dro12 in Loss Oxygen Pressure 10 15 Saturated hydrogenated fish oil acids of 500+ 200 271 0 Pass 400+ 12 to 22 carbon atoms, predominantly Cu to C20 acids (Hydrofol 54). 10 15 Mono-unsaturated Om (Oleic Acid) 500+ 190 S511 .do 400+ [ll l0 15 Saturated and mono-unsaturated oils 500+ 307 380 5 Fail; Ran out of 400+ (glycerides) of 16 to 20 carbon atoms Hub. (Hydrofol Glycerides 42"). 10 7.5 Prfdgmnafntlg 91120;: Saturated acids y roo ci 5. 7.5 C -C Saturated and monounsaturated 500+ 156 305 5 400+ gylcerides (Hydrofol Glycerides 42). 10 10.0 Pnerggmc'manilblx (31163232 5 Saturated acids y ofo ci s 7. 5 Saturated Sperm oil containing l Cid-Cm 500+ 285 5 saturated alcohols (Spermofol 52"). 10 15 Predominantly 016-020 saturated acids 500+ 171 310 0 do 400+ (Hydrofol acids 54) containing 1% polyethylene glycol of 300 mol. Wt.

rafiinate may be used when it contains non-drying oils and furfural in appropriate proportions. Thus, the fatty oil required for soap in conventional soap-thickened greases may be obtained direct from a furfural extraction process Without It will thus be appreciated that various fats and fatty acids may be used. As shown by the data in the foregoing table, the saturated or substantially saturated fatty materials of about 16 to 20 carbon atoms are preferred. The data also show that glycerides and unsaturated fatty materials can be used, but the amount must be limited if water insolubility and structure stability are to be retained.

The greases produced as above described may be modified in the conventional manner by adding thereto the common modifiers such as antioxidants, stringiness agents, tackiness agents, extreme pressure compounds, and the like.

What is claimed is:

1. The process of producing soap and metal furoate lubricating grease compositions which comprises drawin an efiluent liquid containing furfural directly from a furfural solvent oil treating process, adjusting the furfural content and the proportions of an added substantially saturated saponifiable fatty material, together with the lubricating oil content to grease-forming proportions, said furfural content being adjusted to a range between 2 and 20% by weight, based on the total composition, and adding a sufficient quantity of a saponifying base to convert said furfural to a furoate and furfuryl alcohol and to saponify said fatty material in said oil.

2. The process of producing a lubricating grease containing sodium furoate and soap, which comprises drawing from a furfural extraction process an efiluent containing 2 to 20% by weight of furfural, adding ingredients to said efiiuent to adjust the proportions of lubricating oil and a substantially saturated saponifiable fatty material to form soap in grease forming proportions, and treating said adjusted efliuent with 0.6 to 6% by weight on a dry basis, of NaOH to convert said furfural to sodium furoate and furfuryl alcohol and to saponify said fatty material to form a grease structure.

3. Process as in claim 2 wherein said fatty material is hydrogenated fish oil acids of 12 to 22 carbon atoms.

4. The process of producing a lubricating grease which comprises drawing from a furfural extraction process an efiiuent containing 2 to 20% by weight of furfural, reacting said efliuent with a strong alkali to convert said furfural to a furoate and furfuryl alcohol, and adding metal soap of substantially saturated fatty acid and adjusting mineral lubricating oil proportions to form a grease.

5. Process as in claim 2 wherein the furfural content of said oil is about 10% by weight and the fatty material is about 15% of the weight of the final grease.

6. Process of preparing grease compositions which comprises combining in grease forming proportions a lubricating oil, a substantially saturated saponifiable fatty material, and furfural.

said furfural being in a liquid effluent from a furfural solvent refining process, and an alkaline saponifying agent, wherein the furfural is salvaged from said process and converted directly to a furoate and furfuryl alcohol by treatment with said saponifying agent.

7. Process as in claim 6 wherein the furfuryl alcohol is removed from the grease composition by heating.

8. Process as in claim 6 wherein the efliuent contains water and said water is evaporated in the grease forming process.

9. Process as in claim 6 wherein the alkaline material is NaOH.

10. Process as in claim 6 wherein the eflluent contains a major proportion of lubricating oil.

11. Process as in claim 6 wherein the eflluent contains a substantial proportion of the said substantially saturated fatty material which is saponified into said grease.

12. Process as in claim 6 wherein said eflluent contains a major proportion of mineral lubricating oil and said alkaline material is NaOH.

13. Process as in claim 6 wherein said eflluent contains a substantial proportion of the said substantially saturated fatty material and said alkaline material is NaOI-I.

14. Process as in claim 2 wherein said fatty material is stearic acid.

15. Process as in claim 4 wherein said fatty acid is substantially saturated fatty acid of 12 to 22 carbon atoms.

16. Process as in claim 4 wherein the final furoate content of said oil is 3 to 12% and the fatty acid soap content is 3 to 30%.

ARNOLD J. MORWAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,700,056 James Jan. 22, 1929 2,113,754 Zimmer et a1. Apr. 12, 1938 2,245,772 Gothard et al June 17, 1941 2,326,596 Zimmer et al. Aug. 10, 1943 

1. THE PROCESS OF PRODUCING SOAP AND METAL FURATE LUBRICATING GREASE COMPOSITIONS WHICH COMPRISES DRAWING AN EFFLUENT LIQUID CONTAINING FURFURAL DIRECTLY FROM A FURFURAL SOLVENT OIL TREATING PROCESS, ADJUSTING THE FURFURAL CONTENT AND THE PROPORTIONS OF AN ADDED SUBSTANTIALLY SATURATED SAPONIFIABLE FATTY MATERIAL, TOGETHER WITH THE LUBRICATING OIL CONTENT TO GREASE-FORMING PROPORTIONS, SAID FURFURAL CONTENT BEING ADJUSTED TO A RANGE BETWEEN 2 AND 20% BY WEIGHT, BASED ON THE TOTAL COMPOSITION, AND ADDING A SUFFICIENT QUANTITY OF A SAPONIFYING BASE TO CONVERT SAID FURFURAL TO A FUROATE AND FURFURYL ALCOHOL AND TO SAPONIFY SAID FATTY MATERIAL IN SAID OIL. 